Extension-rule



Fl u. www, EXTERN!! EME', APPLICMAQM mi@ 1ML. am im..

11,391,652;e @www 20,1921.

y s; /||||||l||1|frl|u|||lllflmmIlfyqllllllllf l7x1|||||mlllllqullllllvnlllmrlllJulius!!- y// La W42 @a wwwron Ag M TTOHNEYS UNITED STATES PATENT OFFICE.

FREDERICK HENRY FENWIRTH, (')l NEW YORK, N. Y.

EXTENSION-RULE.

'/'0 all fio/1.0m t mag/.concern Be it known that I, FREDERICK HENRY FENWIRTH, a citizen of the United States, and a resident of the city of New York, borough of Manhattan, county and State of New York, have invented a new and Improved Extension-Rule, of which the following is a full, clear, and exact description.

This invention relates to measuring devices, and has reference more particularly to an extension rule in which the elongation of the rule is obtained by moving the various parallel members composing the rule, axially.

An object of this invention is to provide an extension rule which will be strong and durable. y

Another object of this invention is to provide an extension rule which may be used for measuring inside dimensions.

A 'further-object of this invention is yto provide an extension rule so calibrated that the distance between insidesurfaces may be read directly on the rule.

#Reference is to be had to the accompanying drawing forming a part of this specification in which it is understood that the drawing illustrates only one example of the invention, and inwhich,-

Figure 1 is a top view of the uppermost member of the extension rule.

Fig. 2 is a bottom view of the member shown in'Fig. 1. Y

Fig. 3 is a top view of one of themiddle extension members of the rule.

Fig. 4 is a top view of the extension rule in a position for measuring inside dimensions. v

Fig. 5 is a side elevation of the rule.

Fig. 6 is a longitudinal section taken on the line 6--6 of Fig.2.. c

Fig. 7 is a transversesection through two of the extension members on the line 7-7 of Fig. 3.

Fig. 8 is a perspective view of the end of one extension member in combination with the end of a second extension member, said second extension member being cut away to disclose the inner construction.

Fig. 9 is a section on the line 9-9 of Fig. 5.

Referring to the accompanying drawing by numerals, 10 indicates an upper extension member of a rule which is provided on its lower surface with a dove tailed groove Specification of Letters'atent., Patented Sept. 20, 1921.

Applicationk filed January 26, 1920. Serial No. 354,029.

11 which engages a dove tailed tongue 12 on an adjacent member 13. Each of the extension members is provided with beveled edges 14 and the upper member 10 has a flat face 15 formed between the beveled edges 14. One end of the extension member 10 has fixed to it on its lower surface triangularV shaped blocks 16 by means of screws 17, and when said upper extension member 10 is translated axiallythe blocks 16 engage similar blocks 18 fixed to the beveled edges 14 of one end of the member 13 by means of screws 19. A pair of triangular shaped blocks 20 is ixed` to the lower surface of the member 13 opposite the blocks 18 by means of screws 21, and each of the members below the member 13 is provided with blocks similar `to the blocks on said member 13, so that when it is desired to extend the rule to its fullest length, the upper member 10 is engaged by the thumb nail acting in a notch 22, and the upper member 10 is translated axially until the blocks 16 engage the blocks 18 which causes the member 13 also to be translated axially until the blocks 20 engage similar blocks on the .next lower member and so on until all the members are extended to their full length.v In order to secure the rule in its extended position, a tumbler 23 or any suitable pin is slidably mounted in a recess 24 on one end of the lower surface of each extension member adjacent the tongues 12, so that when the members are extended to their `full length, these ytumblers 23 drop into a recess 25 in the upper surface ofthe tongues 12 on the endsof the extension members opposite the'recesses 24. These tumblers 23 are of sufficient length so that when seated in the recess 24 they lie within the vlower surface of the tongues 12 and said tongues are free to slide in the grooves 11, but when the tumblers 23 are seated in the recess 25, the members are held in fixed relation to each other in their extended positions. When it is desired to collapse the members to their shortest position the rule is inverted so that the member 10 is lowermost and upon slightly tapping said rule, the tumblers will drop into the recesses 24 after which the extension members may be collapsed. A recess 25EL is provided on each tongue 12 at a point normally opposite the recess 25 so that when the members are telescoped to their folded position, the tumbler 23 will drop into said recess 25 thus locking the rule in its folded or shortest position.

It is desirable when measuring dimensions between inside surfaces 26 to have the rule direct reading, that is when the end of one extension member stops over a certain position in the adjacent extension member, the exact reading between the inside surfaces 9,6, will be indicated at the end of the first mentioned extension member. For this purpose the upper member 10 is graduated from right to left while the remaining members are graduated from left to right in any suitable units such as inches. lVhen gradu ated in inches it is preferable to have each member indicate 6 inches. To obtain a direct measurement the rule is extended until it abuts against the two inside walls of an article as seen in Fig. 4. It is desired to obtain the distances between these walls. In this particular instance, the second extension member (graduated from left to right) has only been partially pulled out or extended. In order to find the distance between the surfaces, it is necessary to know the point on the lower member, which revisters with the end of the upper member. 2lBy referring to Fig, 4, this point on the lower member is seen to be 9,y indicating that the space between the surfaces is 9 inches. In measuring greater distances, the end of the last fully extended member always indicates on the member below it the distance to be determined.

I would state in conclusion that while the illustrated example constitutes a practical embodiment of my invention, I do not limit myself strictly to the mechanical details herein illustrated, since manifestly the same can be considerably varied without departure from the spirit of the invention as defined in the appended claims.

I'Iaving thus described my invention, I claim as new and desire to secure by Letters Patent:

l. In an extension rule, a plurality of parallel members slidably secured, one to the other, and capable of independent axial movement, said members being provided with a plurality of recesses which register when adjacent members are in any one of a plurality of adjusted positions, and a plurality of tumblers slidably mounted in said recesses adapted to interlock the members when the rule is in one position and to drop to an unlocked position when the rule is inverted to a second position, said members being provided with graduations adapted to indicate the distance between points.

2. In an extension rule, a plurality of parallel members each provided with a dovetail longitudinal groove, a plurality of dovetail, longitudinal tongues associated with said grooves adapted to slidably secure said members together so that said members are capable of independent vaxial movement, said members being also provided with a plurality of recesses which register when adjacent members are in any one of a plurality of adjusted positions, a plurality of tumblers slidably mounted in said recesses adapted to interlock the members when the rule is in one position and to drop to an unlocked position when the rule is inverted to a second position, said members being provided with graduations adapted to indicate the distance between points.

3. In an extension rule, a plurality of parallel members slidably secured, one tothe other, and capable of independent axial movement, means for moving one of said members axially, means associated with the members adapted to move the members axially in succession as the first mentioned member is moved axially, said members being` provided with a plurality of recesses which register when adjacent members are in any one of the plurality of adjusted positions, a plurality of tumblers slidably mounted in said recesses adapted to interlock the members when the rule is in one position and unlock the members when the rule is inverted to a second position, the uppermost member being provided with graduations reading in one direction, and the remaining members being provided with graduations reading in the opposite direction adapted toV indicate directly the distance between points.

FREDERICK HENRY FENWIRTH. 

